The Globe-Miami mining district in which the Van Dyke project occurs is known mainly for its large porphyry copper deposits, including the Miami-Inspiration, Miami East, Pinto Valley, Copper Cities and Castle Dome mines, and copper-bearing veins of the Old Dominion mine.

Porphyry copper deposits consist of disseminated copper minerals and copper minerals in veins, stockworks and breccias that are relatively evenly distributed throughout large volumes of rock. Porphyry copper deposits are typically high tonnage (greater than 100 million tons) and low to medium grade (0.3–2.0% Cu). They are the world’s most important source of copper, accounting for more than 60% of the annual world copper production and about 65% of known copper resources.

The geometry and dimensions of porphyry copper deposits are diverse, in part because of post-ore intrusions, varied types of host rocks that influence deposit morphology, relative amounts of hypogene and supergene ore each of which has different configurations, and erosion and post-ore deformation including faulting and tilting. Porphyry copper deposits commonly are centered on small cylindrical porphyry stocks or swarms of dikes.

The vertical extent of hypogene mineralization in porphyry copper deposits is generally less than or equal to 1 to 1.5km. The predominant hypogene copper sulphide minerals are chalcopyrite, which occurs in nearly all deposits, and bornite, which occurs in about 75% of deposits. Molybdenite, the only molybdenum mineral of significance, occurs in about 70% of deposits. Gold and silver, as by-products, occur in about 30% of deposits.

The Van Dyke copper deposit has a drill-defined, north-easterly strike length of 1500m, a width of 1300m, and a thickness between 40m to over 230m.

Mineralization includes both hypogene (primary sulphide) and supergene (secondary oxidization/enrichment -oxide-silicate+/-sulphide) types, but the latter far outweighs the former in terms of abundance, grade, and therefore economic potential. Secondary copper mineralization comprises most of the Van Dyke deposit. Mineralization, consisting primarily of malachite, chrysocolla, azurite, cuprite and tenorite occurs over a 1,500m horizontal distance principally in tectonically fractured to brecciated panels of Pinal Schist. The secondary minerals in the vicinity of the Van Dyke shaft occur primarily as bands and crustifications, textures that suggest formation was by filling of open spaces, whereas in other parts of the deposit, the secondary copper minerals occur as staining on cleavage planes, in fractures and as in-situ replacement in quartz veins. There are no relict sulphide grains in the upper part of the deposit. Beneath the secondary copper mineralization there exists a weakly developed Supergene zone; containing primarily chalcocite with sparse malachite, azurite and chrysocolla and is transitional down-section locally into weakly-developed zones of hypogene mineralization, primarily located in the central and western parts of the project area.

The Van Dyke deposit is located immediately southwest of the Miami Caved deposit and east of the Miami East deposit. It is separated from the Miami Caved deposit and from the Miami East deposit by the Van Dyke fault. The Van Dyke deposit is interpreted to be the eastern extension of the porphyry copper deposit mined by the Miami-Inspiration operation and the southern extension of the Miami caved porphyry copper deposit. The deposit is covered by from 186m to 627m of alluvium and post-mineral Gila Conglomerate.

The Van Dyke deposit is hosted primarily in the Pinal Schist and to a lesser extent in porphyritic dykes of Schultz granite. Secondary copper mineralization comprises much of the Van Dyke deposit. The Oxide zone consists primarily of malachite, chrysocolla, azurite and cuprite. These copper minerals occur in fractures, in quartz veins and along cleavage planes but primarily in fractured to brecciated areas of Pinal Schist. Beneath the oxide copper mineralization there exists a weakly developed Supergene zone containing mainly chalcocite with sparse malachite, azurite and chrysocolla; it istransitional down-section into local, weakly-developed zones of hypogene chalcopyrite-pyrite-molybdenite mineralization particularly in the center and western parts of the project area. Hypogene copper-molybdenum mineralization is subordinate to the secondary copper mineralization that comprises much of the Van Dyke copper deposit.

The proposed mining method for copper recovery from the Van Dyke deposit is In-situ Copper Recovery methods (ISCR). ISCR has been selected because the Van Dyke deposit is near the town of Miami AZ. Further to this, the fractured nature of the host rock, the presence of saturated joints and fractures within the mineralized zone, and copper mineralization that preferentially occurs along fracture surfaces makes the project a good candidate for ISCR.

In-situ leaching of the oxide resource at Van Dyke is proposed to occur by an injection and recovery well system from underground galleries located just above the oxide deposit, within the Gila Conglomerate. Injection wells will deliver the leachate to the oxide zone, with recovery wells then transporting the dissolved copper in solution to the SX/EW plant at surface. The well holes will be drilled in angled fan patterns from underground galleries and follow an approximate 5-spot pattern with four recovery wells surrounding a single injection well in a repeating pattern, with the average distance between injection and recovery wells designed to be 21m. The final product on site is Grade A copper cathode (99.99% pure) for shipment to the market.

The mine development plan comprises an access ramp from surface for mobile equipment, two declines for access to the production galleries, gallery development within the targeted production zones, and service and ventilation facilities. All underground development is carried out using conventional drill and blast tunneling techniques with mechanized equipment.

The portal will be collared northwest of the Van Dyke Shaft at the 1,085m elevation, and the Main Access ramp will be driven at a 17% grade to the beginning of the Phase 1 Decline elevation of 849m. From there, the Phase 1 Decline descends at grade no more than 17% with 10 galleries extending level off the decline. At the end of the main Phase 1 Decline at elevation 670, gallery 10 branches off to the north and the Phase 1 Egress/Vent Decline continues to the southeast at 17%, ending at elevation 634. The ventilation shaft will be driven by raisebore method to surface at a 72° dip and is to be fitted with a ladder for secondary egress. The Phase 2 Decline branches off the Phase 1 Decline and descends at no more than 17% from elevation 786m to 612m. A short egress way connects the Phase 2 Decline to the Phase 1 Egress/Vent Decline at 53°.

Over 60% of the underground development is completed during preproduction.

The underground development will produce roughly 190,000 m3 of waste rock. All waste rock will be stored in the valley directly adjacent to the portal.

The copper extraction plan is designed to provide the SX-EW plant with PLS to produce 85Mlbs per year, the PLS grade and volume of solution produced by each well varies according to zone, and PLS grade declines with increasing year of operation. Additional wells are brought online each year to meet the targeted needs of the plant.

The processing plant will receive pregnant leach solution (PLS) from the In-situ Copper Recovery (ISCR) leaching operation. The plant will process between 580 to 3900 m3/hr, averaging 2,800 m3/h PLS and produce 38,555 t/year 85Mlb/year as LME grade copper cathode.

The main processing areas will include:
- Copper solvent extraction (SX)
- Copper electrowinning (EW)
- Bleed solution neutralisation
- Reagents and services

The SX circuit will consist of two extract stages and a single strip stage. Based on the expected iron and manganese concentrations in the PLS, a wash stage should not be required in this circuit.

Spent electrolyte from the copper electrowinning process will be used to strip the copper from the loaded organic back into the aqueous phase. The spent electrolyte will have a high sulphuric acid concentration (180 g/L) and this will reverse the extraction reaction, consuming sulphuric acid and producing copper sulphate.